Screw-cutting device



("No Model.)

v I .W. L. BERGEN.

SCREW GUTTING DEVIUE.

Pa'tented- July 19,-1-881.

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UNITED STATE PATENT OFFICE.

WILLIAM L. BERGEN, O F BATAVIA, ILLINOIS.

SCREW-CUTTING DEVICE.

SPECIFICATION forming part of Letters Patent No. 244,427, dated July 19, 1881.

Application filed December 13, 1880. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM L. BERGEN, of Batavia, in the county of -Kaue and State of Illinois, have invented a new and useful Improvement in Screw-Cutting Devices and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

In developing the manufacture of screwcutting dies it appeared essential that the dies should open at a given point and the screw be withdrawn from the dies without reversing the operation by which the screw is cut, and also that the opening of the dies should transpire at a given point, that all the screws may be out precisely alike, and it is important that this be done by the use of simple mechanisms substantial in their construction and operating with accuracy and precision, in order to out the threads of set-screws and other small screws which require accuracy and uniformity in their threads.

The novelty of my invention consists in the construction of the sleeve-plate and the chaserholders and the mechanisms by which they are operated in connection with each other and the die-head.

In the accompanying drawings, Figure 1 represents a side elevation of the die'head and the parts which embrace my invention, with the portion, except the pins D and E,indicated by the dotted lines a o m, Fig. 2, cut away to show the interior construction; Fig. 2, a front view of the same; Fig. 3, a front-end view of one of the chaser-holders detached, and Fig. 4 the front and side view of the sleeve-plate detached.

The same letters of reference refer to the corresponding parts in the different figures.

In the accompanying drawings, Arepresents the die-head, which is intended to be used in connection with lathe and screw machines having turret or other tail stocks. It should be made of steel.

B is a sleeve-plate, which fits accurately into the'die-head A, resting upon the shoulder S, as clearly shown in Fig. 1, the part 0 ot' the said sleeve-plate extending back into the diehead.

0 indicate the chaser-holders, and they are pivoted to the sleeve-plate B by means of the pivot-pins n, which are rigidly attached to the chaser-holders O and pass through the holes lin the sleeve-plate B, and are held in place by the nuts H, as clearly shown in Fig. 1.

E are dowel-pins set in the die-head A, which project above the shoulder S and fit into the small holes 1' in the sleeve-plate B to keep it from turning in the die-head when it fits closely down upon the shoulder S.

F are the chasers, fitting closely in grooves in the chaser-holders, asclearly shown in Fig. 2.

I arehollow screws, madein the shape shown and screwed to a shoulder in thechaser-holders.

J are set-screws, which pass entirely through the hollow screws I and set the chasers F to the desired position.

Kare also set-screws, that are set against the sides of the chasers F.

D are hardened-steel pins, set firmly in the die-head and projecting beyond its face, as shown, where the projecting cams P of the chaser-holders 0 rest against them and hold the chasers securely and firmly in place to out the screw-thread. The projecting cams P of the chaser-holders O are of such shape that if the sleeve-plate B is turned in the die-head A in the direction indicated by the arrow t,Fig. 2, the chaser-holders may be turned back on their pivots n and open the dies so that the screw can be removed or the die-head drawn backover the screw-threads out.

It will be observed that the sleeve-plate B when the check-screw of the tail-stock stops the die-head. The sleeve-plate is drawn forward and the moment it passes the dowel-pins E it turns and the chaser-holders open by turnin g on their pivot-pins n.

Springs may be used, if necessary, to turn the chaser-holders on their pivots.

In cutting small screws there is danger of injuring the thread when the chasers retraverse the thread to remove the screw, and there is also danger of dulling or otherwise injuring the cutting-edges of the chasers.

It will be observed that the special constructions of the various parts of my invention may be varied without changing the results, so far as opening and closing the chaser-holders and chasers and admitting of a quick removal of the screw after it is out without injury to the chasers or screw-thread is concerned; but the above construction is a cheap and substantial form of construction, with few operating parts.

Having thus fully described the construction and operation of my invention, what I claim as new, and desire to secure byLctters Patent, 1s

1. The combination of the chaser-holders 0, provided with cams P, the pins D, the sleeveplate B, dowel-pins E, and die-head A, for the purpose of holding the chaser-holders closed and admitting of their opening, substantially as specified.

2. The dowel-pins E, in combination with the die-head A, sleeve-plate B, and pivoted chaser-holders G, substan tially as specified and 20 shown. 7

3. The die-head A, provided with as houlder,

S, and dowel-pins E, the sleeve-plate B, fitting accurately in the die-head, the chaser-holders O, pivoted to the sleeve-plate B, provided with 2 5 a cam, P, and the pins D, substantially as specified and shown.

WILLIAM L. BERGEN.

Witnesses WM. H. BURNHAM, GEO. O. SPooNER. 

